1. Field of the Invention
The present invention is directed to medical adhesive applicators in which an adhesive is stored in a glass container. More specifically, the present invention is directed to glass treatment methods comprising exposing a glass applicator or container to ammonium sulfate, an acidic gas, a plasma containing silicon dioxide or a silanizing agent in order to remove alkalide materials trapped in the glass or to coat the glass so that the alkalide materials will not contact any adhesive placed in the glass applicator.
2. Description of Related Art
Processes for treating medicament glass containers to decrease the alkalinity of the glass are known.
For example, U.S. Pat. No. 2,046,302 to Bowes discloses a method of neutralizing the alkalinity of the interior surface of hollow ceramic articles by depositing in the article, while it is hot, a pellet of sulfur dioxide, which when subjected to heat of the article, fires and creates an acidic gas. U.S. Pat. No. 2,525,725 to Rodman discloses a method for treating the interior surfaces of open mouth bottles by heating the bottles to a high temperature in the presence of sulfur dioxide.
U.S. Pat. Nos. 2,947,117 and 2,947,615 both issued to Greene et al., disclose a method of reducing the alkalinity of internal surfaces of small mouthed bottles or ampules containing aqueous solutions for medical use by heating the bottles and/or ampules in the presence of an acidic gas. The process is conducted to eliminate or reduce a decrease in potency or an increase in toxicity of the medicaments due to leaching of alkali.
U.S. Pat. No. 3,116,991 to le Clerc discloses a process of dealkalizing glass by heating the glass at elevated temperatures in the presence of ammonium acid sulfate. U.S. Pat. No. 3,348,934 to Hinson et al. discloses the treatment of surfaces of glass containers to reduce surface alkalinity by converting sulfur trioxide to sulfur dioxide by contacting gaseous sulfur trioxide with the glass surface at an elevated temperature followed by washing with water to remove the alkali. U.S. Pat. No. 3,451,796 to Mochel discloses exposing glass to a sulfur oxide atmosphere at a temperature below the strain point of glass to dealkalize the glass surface to increase the acid durability of the glass.
U.S. Pat. No. 4,228,206 to Fabisak discloses a method for reducing the alkali content of the inner surface of glass tubing by introducing an acidic gas (e.g., sulfur dioxide, hydrogen chloride or nitric acid) into the glass tubing at a hot draw stage during formation of the tubing to react with the alkali ions on the inner surface of the glass. U.S. Pat. No. 4,904,293 to Gamier et al. discloses dealkalizing of glass microspheres. U.S. Pat. No. 5,292,354 to Hecq et al. discloses a method of producing dealkalized sheet glass in which the glass sheet is subjected to at least one acid gas in multiple stages at different elevated temperatures. The entire disclosures of all of the foregoing references are hereby incorporated by reference herein.
However, there continues to be a need to eliminate alkalide materials that may come in contact with medical adhesives in glass applicators.
One group of such adhesives is the monomeric forms of alpha-cyanoacrylates. Reference is made, for example, to U.S. Pat. Nos. 3,527,841 (Wicker et al.); 3,722,599 (Robertson et al.); 3,995,641 (Kronenthal et al.); and 3,940,362 (Overhults), which disclose that alpha-cyanoacrylates are useful as surgical adhesives. The entire disclosures of all of the foregoing references are hereby incorporated by reference herein.
Typically, when used as adhesives and sealants, cyanoacrylates are applied in monomeric form to the surfaces to be joined or sealed, where, typically, in situ anionic polymerization of the monomer occurs, giving rise to the desired adhesive bond or seal. Implants, such as rods, meshes, screws, and plates, may also be formed of cyanoacrylate polymers, formed typically by radical or anionic-initiated polymerization.
However, a drawback to the in vivo biomedical use of alpha-cyanoacrylate monomers and polymers has been their potential for causing adverse tissue response. For example, methyl alpha-cyanoacrylate has been reported to cause tissue inflammation at the site of application. The adverse tissue response to alpha-cyanoacrylates appears to be caused by the products released during in vivo biodegradation of the polymerized alpha-cyanoacrylates. It is believed that formaldehyde is the biodegradation product most responsible for the adverse tissue response and, specifically, the high concentration of formaldehyde produced during rapid polymer biodegradation.
In U.S. Pat. No. 5,328,687, the entire contents of which are hereby incorporated by reference, the use of formaldehyde scavengers has been proposed to improve biocompatibility of alpha-cyanoacrylate polymers, whose biodegradation produces formaldehyde, for use in in vivo applications. In addition, U.S. patent application Ser. No. 08/714,288, filed Sep. 18, 1996, the entire disclosure of which is incorporated herein by reference, discloses a biocompatible pH modifier effective to regulate the pH of an immediate environment of the in situ cyanoacrylate polymer.
Various compounds can affect polymerization of alpha-cyanoacrylate monomers. Acids inhibit or slow polymerization (e.g., Leonard et al., U.S. Pat. No. 3,896,077), and bases accelerate polymerization (e.g., Coover et al., U.S. Pat. No. 3,759,264 and Dombroski et al., U.S. Pat. No. 4,042,442). For example, U.S. Pat. No. 3,759,264 to Coover et al., the entire disclosure of which is incorporated herein by reference, discloses that 2-cyanoacylate adhesive compositions rapidly polymerize in the presence of weakly basic catalysts such as water, alcohols and amines. Similarly, U.S. Pat. No.3,759,264 to Coover et al., the entire disclosure of which is incorporated herein by reference, discloses that a basic material such as amines and alcohols can be added to accelerate the polymerization of monomeric esters of .alpha.-cyanoacrylic acid.
Because alkalide materials negatively affect the shelf life of monomeric adhesives by initiating premature polymerization as indicated, for example, by an increased viscosity, there is a need to eliminate alkalide materials that come in contact with medical adhesives in glass applicators.